Serine proteases (SPs) constitute a very important family of enzymes, both physiologically and pathologically. The effects produced by these proteins have been explained by their proteolytic ...activity. However, the discovery of pharmacologically active SP molecules that show no enzymatic activity, as the so‐called pseudo SPs or SP homologs (SPHs), has exposed a profoundly neglected possibility of nonenzymatic functions of these SP molecules. In this review, the most thoroughly described SPHs are presented. The main physiological domains in which SPHs operate appear to be in reproduction, embryonic development, immune response, host defense, and hemostasis. Hitherto unexplained actions of SPs should therefore be considered also as the result of the ligand‐like attributes of SPs. The gain of a novel function by an SPH is a consequence of specific amino acid replacements that have resulted in a novel interaction interface or a ‘catalytic trap’. Unraveling the SP/SPH interactome will provide a description of previously unknown physiological functions of SPs/SPHs, aiding the creation of innovative medical approaches.
Serine protease homologs (SPHs) are pharmacologically active SP molecules without enzymatic activity. SPHs operate mainly in reproduction, embryonic development, immune response, host defence, and hemostasis. The gain of a novel function by an SPH is a result of specific amino acid replacements leading to a novel interaction interface or a ʹcatalytic trapʹ. SPH interactome is the key to decipher novel physiological functions of SPHs and to develop innovative medical approaches.
This study presents the comprehensive experimental investigation of the microstructure, mechanical and fatigue properties of a new high-strength aluminium alloy AA 6086, which was developed from a ...commercial aluminium alloy AA 6082. The new alloy possesses a higher content of Si, and, it also contains Cu and Zr. The alloy was characterised in the as-cast condition after homogenisation, extrusion, and T6 heat treatment. Light microscopy, scanning and transmission electron microscopy with energy dispersive spectrometry were used to analyse the microstructure and the fractography of broken specimens. The quasi-static and fatigue tests were performed on the MTS Landmark 100 kN servo-hydraulic test machine, controlled with a mechanical extensometer with a 25 mm gauge length. The quasi-static strength of the analysed aluminium alloy AA 6086 was found to be significantly higher if compared to some other AA 6xxx alloys, while the ductility was kept almost the same. The experimental results of the comprehensive fatigue tests in a Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) regime showed a good fatigue resistance, and represent a good basis for engineering design applications of the newly developed aluminium alloy AA 6086.
•A novel aluminium alloy AA 6086 was developed from a commercial alloy AA 6082.•The new alloy possesses a higher content of Si, and, it also contains Cu and Zr.•LCF and HCF behaviour of AA 6086 was investigated experimentally.•The quasi-static strength was found to be higher if compared to some other AA 6xxx alloys.•The new alloy showed a good fatigue resistance.
•The fatigue behaviour of a novel aluminium alloy AA 6086 was investigated.•The results were compared with the conventional alloy AA 6110A.•The microstructures of both alloys were found to be quite ...similar.•The quasi-static strength of a novel alloy was found to be significantly higher.•The novel alloy AA 6086 is more suitable for the high-cycle fatigue regime.
The proposed research presents the comprehensive investigation of the Low Cycle Fatigue (LCF) behaviour of two high-strength aluminium alloys of series AA 6xxx: the conventional alloy AA 6110A and the newly developed alloy AA 6086. Both alloys were characterised in the as-cast condition after homogenisation, extrusion, and T6 heat treatment.
The quasi-static strength and hardness of the aluminium alloy AA 6086 were found to be significantly higher if compared to the AA 6110A alloys, while the ductility was a little bit smaller. The LCF tests showed that the AA 6086 alloy is more suitable for the high-cycle fatigue regime. On the other hand, the engineering advantage of the AA 6110A alloy is only for low-cycle fatigue applications if less than 100 loading cycles are expected in the service life of the analysed structure. The fatigue cracks formed predominantly on the α-AlMnSi intermetallic particles in both alloys, and, during LCF tests, exhibited small crack propagation. The area of the fatigue crack growth was much smaller than the area of the forced fracture. At smaller amplitude strains the fatigue striations were present at the fracture surface, while, at higher amplitude strains, they were not present. The obtained experimental results represent a good basis for engineering design applications of the analysed alloys AA 6086 and AA 6110A.
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•The LCF-behaviour of Al-alloys was investigated experimentally and computationally.•A comprehensive statistical approach was proposed to evaluate the experimental results.•An ...elastic–plastic kinematic material model was applied in the computational model.•The strain life approach with Morrow correction was used to obtain the fatigue life.•Comparison between computational and experimental results showed a good agreement.
This study presents the experimental and computational analysis for determining the fatigue life of the auxetic cellular structures made of aluminium alloys. For the fatigue life calculation, the strain life approach was applied in the framework of the ANSYS software. The obtained experimental results were evaluated using the comprehensive statistical analysis, and presented in the form of different fatigue-life curves.
Based on the reasonable agreement between computational and experimental results the proposed computational model was validated and can be used further for the fatigue studies of various auxetic structures made of Al-alloys.
A coupled process of ultrasonic spray pyrolysis and lyophilisation was used for the synthesis of dried gold nanoparticles. Two methods were applied for determining their melting temperature: uniaxial ...microcompression and differential scanning calorimetry (DSC) analysis. Uniaxial microcompression resulted in sintering of the dried gold nanoparticles at room temperature with an activation energy of 26–32.5 J/g, which made it impossible to evaluate their melting point. Using DSC, the melting point of the dried gold nanoparticles was measured to be around 1064.3°C, which is close to pure gold. The reason for the absence of a melting point depression in dried gold nanoparticles was their exothermic sintering between 712 and 908.1°C.
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